macOS release fix, temporarily disable ubuntu release #1133

Job	Run time
Code linters	2m 5s
Build Docker image	1m 42s
Unit tests in ubuntu-20.04	18m 58s
Run PEEPS tests	10m 4s
Acceptance tests (basic \|\| basic-raft \|\| (advanced && raft) \|\| networks/typical::raft)	19m 32s
Acceptance tests (basic \|\| basic-istanbul \|\| (advanced && istanbul && !block-heights) \|\| networks/typical::istanbul)	21m 50s
Acceptance tests (basic \|\| basic-istanbul \|\| (advanced && istanbul && !block-heights) \|\| empty-block-period \|\| block-reward \|\| networks/typical::qbft)	20m 53s
Acceptance tests (validator-management && networks/template::istanbul-3plus1)	8m 17s
Acceptance tests (validator-management && networks/template::qbft-3plus1)	7m 55s
Acceptance tests (multitenancy && networks/plugins::raft-multitenancy)	7m 52s
Acceptance tests (migration && networks/template::istanbul-4nodes)	5m 18s
Acceptance tests (migration && networks/template::raft-4nodes)	4m 53s
Acceptance tests (basic \|\| networks/typical::raftmps)	15m 23s
Acceptance tests (basic \|\| networks/typical::istanbulmps)	21m 17s
Acceptance tests (basic \|\| networks/typical::qbftmps)	20m 42s
	3h 6m 41s

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